The prison in the town of Bannu was attacked by Islamist militants with guns and rocket propelled grenades, allowing the inmates to escape.

Doors were knocked down and locks were broken. Bullet holes could be seen on the walls of the prison cells and remnants of the grenades were found at the entrance of the jail.

The Taliban in Pakistan claimed responsibility for the assault, which triggered clashes that left several people wounded.

A spokesman said they had freed hundreds of their comrades in the attack, and that many of the escaped inmates had reached their destinations, while others were on their way.

The claim could not yet be verified, but if the Taliban did free the prisoners, it would be a big psychological blow to Pakistani security forces who are saying that are gaining ground in flushing out militants.

Security officials say only some of the prisoners who escaped were militants.

But a jail official in Bannu said at least one of them was a dangerous criminal, involved in an an assassination attempt against former president Pervez Musharraf.

Suicide bombings in Pakistan have eased in recent months. This could mean that the crackdowns are working and have weakened the Taliban, although some say the group could just be changing tactics.